Then she’s not your girlfriend and is rather just a friend that you are calling a girlfriend.
It’s important to understand that people have different comfort levels when it comes to intimacy and relationships. There is a kind of universal language we use to describe what we are to each other, but the language doesn’t really say anything about the underlying interaction you have.
She might have reasons for calling you her boyfriend that have absolutely nothing to do with you. For example she might have lots of boys interested in her and she just wants to fend them off. So she picks the least threatening guy she can find and makes him her ‘boyfriend’.
You can break up with her or continue to let her use you. One thing I might do if I were you would be to say nothing about it, but just ignore her and act like you’re single. Eventually she’ll drop the fiction herself.
But I wouldn’t hold my breath thinking you’ve got a shot at actually being her boyfriend. Not even wanting to spend time with you alone, she’s just not into you.